I have to have AF assist during dark wedding receptions and I was angry that the smaller transmitter left off an AF assist. I do not need my on camera flash to produce light (I rely on off camera lights), however I need it to control the other flashes and provide a reliable AF assist. When the 430ex iii came out I thought that it would make a great master for my off camera flashes, but I have read on this form that the AF assist only works with the center AF point, and that is not acceptable. I shoot with the 1dx2 and as good as it is, it can't focus in complete darkness. The 600ex is large and it puts a lot of stress on my hands and wrists throughout a long event. I would love to know if it is possible to take the flash part off of a 600ex and only leave the battery compartment, controls, and AF assist. Is there anyone who would be able to do that? I doubt Canon would do it.